1. Field of the Invention
The present invention relates generally to aerodynamic, flight dynamics, and hydrodynamic devices, and more specifically to an airfoil or hydrofoil having independently movable surfaces on each side or surface thereof and incorporating selective fluid flow means through the surface(s), i.e., suction or xe2x80x9cblownxe2x80x9d surfaces. The present invention is adaptable to various devices in the field of aerospace engineering as well as in the marine environment. Hence, the term xe2x80x9cplanexe2x80x9d as used throughout the present disclosure, refers to a generally planar lifting or control surface (e.g., wing, fin, etc.) for dynamic operation in a fluid, and is adaptable for use in any practicable fluid, including gases such as air and liquids such as water.
2. Description of the Related Art
The development of aviation and the maritime industries has led to ever more efficient shapes and configurations for aerospace craft and marine vessels. Numerous advances have occurred over the years, including laminar flow shapes, leading and trailing edge devices for airfoils, etc. However, all such surfaces or planes rely upon the principle of differential pressure upon opposite surfaces of the plane in order to develop a lifting or turning force, depending upon their orientation and function.
The differential pressure is developed by moving a fluid over one surface of the plane at a greater velocity than the fluid moving over the opposite surface of the plane. Bernoulli explained this principle in the eighteenth century, developing the mathematical concept that pressure varies inversely according to the square of the fluid velocity over a given surface. Accordingly, most surfaces which are intended to provide a generally constant force in a predetermined direction (e.g., aircraft wings) are configured with a greater curvature over one side thereof than the opposite side, and/or operate at a positive angle of attack to develop the desired pressure differential.
Later, others recognized other means of providing such differential pressure by mechanically accelerating the fluid flow over one side of the surface. Aircraft have been developed using xe2x80x9cblown surfacesxe2x80x9d or xe2x80x9cblown flaps,xe2x80x9d in which jet exhaust is expelled over the upper surface of a wing to increase the velocity of the flow over that area and generate relatively greater lifting force. Other devices have been developed for entraining the fluid flow adjacent to the surface of the plane, by moving the surface to reduce the velocity differential between the surface and the fluid stream. This reduces the drag of the surface upon the fluid to provide a greater fluid velocity, or may accelerate the fluid to a velocity greater than that of the surface through the fluid, to provide a greater differential in velocity between the plane and the fluid for greater lifting force. Such devices are described further below.
As the sciences of aerodynamic and hydrodynamic engineering developed, the problem of control of the boundary layer of fluid immediately adjacent the surface became apparent. It was recognized as early as the 1930s that significant improvements in performance could be achieved, if some means were found to prevent the boundary layer from becoming turbulent immediately adjacent the surface, and/or to eliminate or minimize such turbulence when it occurred. xe2x80x9cLaminarxe2x80x9d airfoils and other shapes were created as a result, with these surfaces and shapes serving to delay, but not eliminate, the onset of turbulent flow.
Still later, it was recognized that providing some means of drawing the turbulent layer of fluid immediately adjacent the surface, into the surface (i.e., suction), served to prolong the laminar flow of fluid over the surface and thus improve performance of the craft. In some instances, applying fluid to the exterior of the surface can serve to enhance performance as well, as by xe2x80x9ctrippingxe2x80x9d the boundary layer ahead of the normal transition point to preclude excessive turbulence at the transition from laminar to turbulent flow.
However, none of the devices known to the present inventors provides an independently movable surface on each side of a two surface plane, as well as means for inducing fluid flow through the surface (either suction or blowing), as provided by the present invention. The present invention provides a significant improvement over the prior art, by providing independently movable surfaces upon both sides of the plane and means for producing fluid flow through the movable surfaces. Thus, fluid flow may be accelerated across one surface by moving the surface in the direction of flow (opposite the direction of travel), while retarding flow over the opposite surface by moving the surface against the direction of flow (in the direction of travel). This provides a greater differential in fluid velocity over the two surfaces, thereby increasing the pressure differential between the surfaces to provide greater differential forces between the sides than are attainable with prior art devices, to improve lift, reduce drag, and improve the lift to drag ratio (aerodynamic performance). Also, moving the lower surface in the direction of flow reduces drag by reducing shear stress on the surface. The provision of blown or suction flow through the movable surfaces provides additional benefits in the control of the boundary layer immediately adjacent to the surface.
The present invention may also provide a delay in flow separation over one or both surfaces of the plane, by providing a predetermined velocity differential between the moving surface and the relative flow. By adjusting the velocity of the two independent moving surfaces of the present invention, a delay in separation may be achieved by adding momentum to the boundary layer over the upper surface, particularly at higher angles of attack. The provision for blowing or drawing fluid through the surface, provides further benefits in control of the separation of the fluid over and around the surface(s).
A discussion of the related art of which the present inventors are aware, and its differences and distinctions from the present invention, is provided below.
U.S. Pat. No. 1,674,169 issued on Jun. 19, 1928 to Anton Flettner, titled xe2x80x9cArrangement For Exchanging Energy Between A Current And A Body Therein,xe2x80x9d describes a series of embodiments generally employing cylinders to develop a Magnus effect or force. In some embodiments multiple cylinders are used, while in other embodiments at least a forward and a rearward cylinder are employed with a movable surface extending around the cylinders. None of the embodiments disclosed by Flettner provides independently movable surfaces on each side of the airfoil or hydrofoil, which independent dual surfaces are a part of the present invention. In addition, Flettner does not disclose any means for causing a fluid to flow through his movable (or stationary) surfaces, which fluid flow through the surface(s) is a part of the present invention.
U.S. Pat. No. 1,785,300 issued on Dec. 16, 1930 to Filiberto de la Tour Castelcicala, titled xe2x80x9cRolling Apron For Airplane Wings,xe2x80x9d describes an airfoil having a series of endless flexible belts which wrap about both the upper and lower surface and around the leading and trailing edge of the wing. Drive rollers are provided at the leading and trailing edges, with pinions engaging toothed bands disposed along the inner surfaces of the belts. The upper and lower surfaces of the de la Tour Castelcicala wing are interdependent, with the velocity of one surface determining the velocity of the opposite surface. If the upper surface of the de la Tour Castelcicala wing is traveling forwardly relative to the wing structure, then the lower surface must travel rearwardly. The planes of the present invention, with their two independently moving opposite surfaces, overcomes this deficiency. Moreover, de la Tour Castelcicala did not provide any actuation or control means for his movable surface, nor did he specify any direction of surface movement for optimum effect. It is also noted that de la Tour Castelcicala does not provide any means of moving a fluid through the surfaces of his airfoil.
U.S. Pat. No. 1,840,594 issued on Jan. 12, 1932 to Victor Minor, titled xe2x80x9cAeroplane,xe2x80x9d describes at least one embodiment comprising a wing having a single endless belt traveling about both the upper and lower surfaces of the wing. While Minor also describes means for providing power to drive his system, he does not describe any means of controlling the system to provide varying relative velocities as desired. Thus, the Minor wing is basically similar to that of de la Tour Castelcicala patent discussed above, with its lack of independently movable opposite surfaces. It is also noted that Minor does not provide any means of inducing a fluid flow through the surface of his wing.
U.S. Pat. No. 1,879,594 issued on Sep. 27, 1932 to Serge Trey, titled xe2x80x9cAeroplane Wing,xe2x80x9d describes an airfoil having a rotating cylindrical leading edge. The Trey device does not cover essentially the entire upper and lower surfaces of the airfoil with a moving surface, as provided by the present invention. Moreover, while Trey discloses a means of powering his rotary leading edge, he is silent regarding the direction of rotation and also any control means for the device. The present disclosure includes control means for adjusting the amount of pressure, or differential pressure, produced by the present movable surfaces. As in the case of other fluid control surfaces of which the present inventors are aware, Trey fails to provide any means of passing air or other fluid through the rotating leading edge surface of his wing.
U.S. Pat. No. 1,957,413 issued on May 1, 1934 to Albert O. Price, titled xe2x80x9cAir Control Apparatus,xe2x80x9d describes a concept having at least one embodiment in which air is drawn through a porous upper wing surface and discharged through a porous lower wing surface. No movable airfoil surfaces are provided by Price, nor is any means provided for selectively reversing the fluid flow from pressure to suction as desired, as provided by the present invention.
U.S. Pat. No. 2,928,626 issued on Mar. 15, 1960 to Ovid Tino, titled xe2x80x9cSustaining Airfoil With Retractable Cylindrical Rotor,xe2x80x9d describes a wing having a rotating cylindrical trailing edge, essentially the opposite configuration to that of the Trey U.S. Patent discussed immediately above. Tino uses circulation theory and additive slipstream vectors to show that the addition of the trailing edge cylinder causes the rearward separation to extend downward beneath the trailing edge of the wing, thereby providing greater lifting force. However, he does not describe any means of moving either the upper or the lower surface of the airfoil to provide higher lift coefficients and/or to maintain attached flow at higher angles of attack, nor of providing fluid flow through the airfoil surface to enhance flow over the surface, as achieved by the present invention.
U.S. Pat. No. 3,128,973 issued on Apr. 14, 1964 to Robert E. Dannenberg, titled xe2x80x9cPorous Material,xe2x80x9d describes a composite having a porous surface sheet with a honeycomb structure therebeneath. Both the porous surface sheet and the honeycomb can be adjusted as desired to provide the desired permeability and porosity. However, Dannenberg does not provide any means of constructing such composite sheets in endless flexible bands to form movable airfoil or hydrofoil surfaces, as provided by the present invention, nor does he disclose any means of powering such movable surfaces nor of providing the desired fluid pressure or suction through his porous surfaces.
U.S. Pat. No. 3,149,804 issued on Sep. 22, 1964 to Charles J. Litz, Jr., titled xe2x80x9cAnti-Stall System,xe2x80x9d describes a wing having a porous upper surface which communicates with a venturi which draws air through the porous upper wing surface. The venturi is energized by a chemical propellant, which expands to create a pressure drop to draw the air in through the porous wing surface. The effect is relatively short lived, and is intended only to recover from a stalled condition having an extremely short duration. Litz, Jr. does not provide any form of movable surfaces, nor does he provide any means of selectively controlling suction or blown flow through opposite sides of a surface.
U.S. Pat. No. 3,448,714 issued on Jun. 10, 1969 to John D. Brooks, titled xe2x80x9cFin And Revolving Cylinder Bidirectional Steering Actuator,xe2x80x9d describes the use of rotating cylindrical leading and/or trailing edge devices installed in the fins of a submersible vessel. The resulting system is similar to the devices described in the U.S. Patents to Trey (leading edge device) and Tino (trailing edge device), discussed above, with a similar effect. Brooks recognizes the efficacy of such rolling leading and/or trailing edges, and their adaptability to marine use as well as aeronautical use. The present disclosure also recognizes the similarities and applications between aviation and maritime dynamics. However, Brooks is silent regarding any provision for moving the opposite surfaces of the fin itself, rather than only the leading and/or trailing edges, and for blowing or drawing air or other fluid through the surface.
U.S. Pat. No. 5,114,100 issued on May 19, 1992 to Peter K. C. Rudolph et al., titled xe2x80x9cAnti-Icing System For Aircraft,xe2x80x9d describes various embodiments of a system for blowing heated air over the leading edge surfaces of a wing, primarily to melt ice and to prevent ice from forming on those surfaces. Rudolph et al. also note that their system can be used to draw air into the leading edge to promote laminar flow, as well. The present invention teaches away from any means for drawing air into or blowing air out of the leading edge, as this area is normally in an area of laminar flow in any event. The present invention provides means for producing an airflow through the surface behind the leading edge structure thereof, in combination with means for moving either or both the upper and lower surfaces. Rudolph et al. do not disclose any means of continually moving the surface of their wing at any location thereover.
U.S. Pat. No. 5,180,119 issued on Jan. 19, 1993 to Jean-Paul Picard, titled xe2x80x9cVertical Lift System Through Tangential Blowing Of Air Jets Channelled Over The Top Of Rotating Cylinders,xe2x80x9d describes a partially masked Magnus cylinder having an air jet blowing essentially tangentially thereover. A relatively small area of the cylinder is exposed, with the air jet blowing from the leading edge of this exposed area. The use of a Magnus cylinder having a fixed radius, is completely different from the plural moving belts of the present movable surface airfoil. In any event, Picard does not disclose any means for passing air through the surface of the Magnus cylinder.
U.S. Pat. No. 5,222,698 issued on Jun. 29, 1993 to Philip A. Nelson et al., titled xe2x80x9cControl Of Boundary Layer Flow,xe2x80x9d describes a system utilizing acoustic sensors (microphones) disposed in a normally turbulent area to detect the sounds produced by turbulent flow. Passages are located upstream of the microphones, for drawing air therein to hold the boundary layer close to the surface in order to reduce turbulent flow. Suction is controlled by a program which is in turn actuated by turbulent flow detected by the microphones. No blowing of air through the passages is disclosed by Nelson et al., nor is any means for moving the surface(s) with or against the airflow, as provided by the present invention.
U.S. Pat. No. 5,263,667 issued on Nov. 23, 1993 to Raymond H. Horstman, titled xe2x80x9cPerforated Wing Panel With Variable Porosity,xe2x80x9d describes the provision of a porous surface for drawing airflow therethrough, with the porosities varying in cross sectional area according to the air pressure over the surface at that given location on the surface. The structure used to provide the suction through the porosities is essentially the same as that disclosed in the ""100 U.S. Patent to Rudolph et al. discussed further above, with the assignee for both the ""100 and ""667 U.S. Patents being the Boeing Company. As in the case of the ""100 U.S. Patent to Rudolph et al., the ""667 U.S. Patent does not disclose any means for continually moving any surface of an airfoil or plane, as provided by the present invention.
U.S. Pat. No. 5,366,177 issued on Nov. 22, 1994 to Steven P. DeCoux, titled xe2x80x9cLaminar Control Apparatus For Aerodynamic Surfaces,xe2x80x9d describes a wing cuff assembly for removable installation upon an existing wing structure. The cuff assembly includes a plurality of channels therein, which communicate with the porous outer surface of the cuff to provide suction therethrough. Means are also provided within the cuff for controlling the suction through various areas of the porous surface. The Mitchell cuff assembly cannot provide the movable surface(s) of the present invention, due to its removable installation along the leading edge of an existing conventional wing structure.
U.S. Pat. No. 5,447,283 issued on Sep. 5, 1995 to Runyon H. Tindell, titled xe2x80x9cBlown Boundary Layer Control System For A Jet Aircraft,xe2x80x9d describes a turbojet engine nacelle having a series of orifice areas for providing blown airflow at various areas within and without the nacelle. Air may be provided at the nacelle lip, within the duct, and/or over the afterbody of the nacelle, to control boundary layer turbulence at those locations as generated by different conditions of engine power, airspeed, and angle of attack of the nacelle. A computer is used to control the airflow, which is provided by the engine compressor. Tindell does not disclose any form of movable surface for the nacelle, either within or without the nacelle, nor does he disclose any boundary layer suction means, as provided by the present movable surface plane invention.
U.S. Pat. No. 5,590,854 issued on Jan. 7, 1997 to Solomon Shatz, titled xe2x80x9cMovable Sheet For Laminar Flow And Deicing,xe2x80x9d describes a sheet having porous and nonporous areas, extending between a pair of rollers. The rollers are positioned so the sheet is disposed only over the upper forward portion of the airfoil, rather than about the majority of the upper and lower surfaces, as in the present invention. More importantly, the Shatz invention can only translate back and forth between the porous and nonporous areas, to provide for suction over this area of the wing or a smooth surface for laminar flow. As the two ends of the Shatz device are secured to opposed rollers, it cannot move continuously in a single direction, as provided by the present movable surfaces.
U.S. Pat. No. 5,772,156 issued on Jun. 30, 1998 to Pradip G. Parikh et al., titled xe2x80x9cAircraft Boundary Layer Control System With Discharge Transpiration Panel,xe2x80x9d describes a system wherein suction is applied to various aircraft surfaces (e.g., the upper surface of the wing), and discharged through a porous transpiration panel located in an area of turbulent flow in order to minimize drag produced by the injection of air into the slipstream. The discharge of airflow into the slipstream is incidental to the suction developed for boundary layer control and no direct control is provided of such airflow discharge, whereas the present invention includes control means for such discharge, as well as suction and control means therefor. Also, Parikh et al. do not provide any means for continuously moving the surface(s) of a plane, as provided by the present invention.
U.S. Pat. No. 5,791,601 issued on Aug. 11, 1998 to D. Stefan Dancila et al., titled xe2x80x9cApparatus And Method For Aerodynamic Blowing Control Using Smart Materials,xe2x80x9d describes a blown trailing edge surface wherein a spanwise duct provides airflow to a spanwise slot located on the upper surface of the airfoil adjacent the trailing edge thereof. Dancila et al. utilize an electrically actuated xe2x80x9csmartxe2x80x9d material which bends when electrically energized, to selectively move a shutter for opening and closing the trailing edge slot. No means for providing suction is disclosed by Dancila et al., nor is any means of moving any of the airfoil surfaces disclosed in the Dancila et al. ""601 U.S. Patent.
U.S. Pat. No. 5,813,625 issued on Sep. 29, 1998 to Ahmed A. Hassan et al., titled xe2x80x9cActive Blowing System For Rotorcraft Vortex Interaction Noise Reduction,xe2x80x9d describes a system wherein air may be selectively blown or drawn through the porous upper and lower forward surfaces of a helicopter rotor blade. While Hassan et al. state that the airflow may be cyclically controlled, depending upon the position of the rotor blade, no disclosure is made of any mechanism for controlling the airflow. In any event, Hassan et al. do not provide any form of movable surface for either the upper or lower surfaces of the airfoil. The present invention provides a selectively continuously movable upper and/or lower surface, in combination with a porous surface(s) and means for selectively controlling suction or outflow through the porous surface(s) for boundary layer control.
U.S. Pat. No. 6,109,565 issued on Aug. 29, 2000 to Lloyd H. King, Sr., titled xe2x80x9cAir Craft Wing,xe2x80x9d describes a system wherein air is forced through a series of openings in the upper and lower surfaces of a wing, with the air being discharged rearward over the upper surface and forwardly beneath the lower surface. This has the effect of creating a higher velocity airflow over the upper surface, while slowing the velocity and increasing the pressure beneath the wing. The control and actuation means are only very generally disclosed, and do not appear to provide an enabling disclosure for those components. King, Sr. describes the openings or passages in the wing surfaces as being integrally formed with the fixed surfaces of the wing. No laterally movable surface for the wing is disclosed by King, Sr., as is provided by the present movable surface airfoil invention.
U.S. Pat. No. 6,142,425 issued on Nov. 7, 2000 to Erian A. Armanios et al., titled xe2x80x9cApparatus And Method For Aerodynamic Blowing Control Using Smart Materials,xe2x80x9d describes various alternative embodiments of the device disclosed in U.S. Pat. No. 5,791,601 to the same inventors, discussed further above. The ""425 U.S. Patent is a continuation-in-part of the ""601 U.S. Patent, and the same points of distinction between the disclosure of the ""601 U.S. Patent and the present invention and noted in the discussion of the ""601 U. S. Patent further above, are seen to apply here as well.
U.S. Pat. No. 6,216,982 issued on Apr. 17, 2001 to Juergen Pfennig et al., titled xe2x80x9cSuction Device For Boundary Layer Control In An Aircraft,xe2x80x9d describes a system employing one or more venturis located within the bypass or other area of a turbofan engine. The venturi(s) produce a suction which draws air from the leading edge and/or upper surface of the wing, through porous panels affixed thereto. No means of selectively blowing air through the panels is possible, using the venturi system of Pfennig et al. Moreover, Pfennig et al. do not provide any means for moving the surface(s) of the wing, whereas the present invention includes both movable surfaces and means for drawing air or fluid through or discharging air or fluid from the porous moving surfaces.
British Patent Publication No. 233,083 accepted on May 7, 1925 to Hugh O. Short, titled xe2x80x9cImprovements In And Connected With Sustaining Devices For Aircraft,xe2x80x9d describes several embodiments of rotary devices installed with airfoils. One of the embodiments discloses a single continuous belt surrounding the entire airfoil. However, Short does not provide for two separate and independent belts upon opposite surfaces of the airfoil, as provided by the present invention, nor does he disclose any means of controlling his roller or belt systems. Moreover, Short does not provide any means of drawing air through or blowing air from the surfaces of his wing. In contrast, the present movable surface plane invention provides such movable surface control means in addition to the various double belt embodiments and selective blowing or suction through the surfaces of the plane.
British Patent Publication No. 332,754 accepted on Jul. 31, 1930 to Filiberto de la Tour Castelcicala, titled xe2x80x9cA Traveling Covering Apron Or The Like For Airplane Wings,xe2x80x9d describes a movable surface comprising a single belt which passes completely around the entire airfoil, excepting the control surfaces. While Castelcicala provides separate moving belts surrounding an aileron or flap at the trailing edge of the wing, he does not provide separate, independent movable surfaces for both the upper and lower surfaces of the wing or control surfaces, as provided by the present invention. Moreover, Castelcicala does not provide any means of drawing or blowing air through a porous movable airfoil or other plane surface, as provided by the present invention.
Italian Patent Publication No. 301,844 released on Oct. 13, 1932 to Eugenio Norzi illustrates a movable surface airfoil, with FIG. 3 showing separate belts over upper and lower wing surfaces. However, Norzi only discloses such belts on a wing; no suggestion is made of such a system for any aircraft control surfaces. Norzi illustrates only the forward fuselage and right wing in FIG. 5 of the drawings, with no illustrations being provided of any stabilizing or control surfaces. Moreover, Norzi indicates unidirectional movement of his moving surfaces, with both the upper and lower surfaces traveling in a forward direction, according to the directional arrows in the double surface airfoil of FIG. 3 and Norzi does not provide any form of blowing or suction flow through any of his airfoil surfaces, whereas the present invention provides both bidirectional belt movement and airflow through the surfaces.
French Patent Publication No. 1,053,332 published on Feb. 2, 1954 to Casimir Villedary illustrates various embodiments of a movable surface airfoil which is employed upon both the wings and horizontal control surfaces of an aircraft. While FIG. 4 apparently discloses a turbojet powered aircraft, it should be noted that the craft is equipped with straight (unswept) wings. This is apparent due to the single rectangular movable surface panel illustrated in that FIG., which appears to be normal to the fuselage at the wing root. Any suggestion of wing sweep would appear to be due to the perspective provided in the FIG. 4 drawing. Moreover, no suggestion is made of any means for controlling the speed of the moving belts, nor of any independent operation of the upper belt relative to the lower belt, as provided by the present system. Finally, Villedary does not disclose any means of blowing or drawing air through the moving surfaces.
European Patent Application No. 532,093 published on Mar. 17, 1993 to the Boeing Company, titled xe2x80x9cPerforated Wing Panel With Variable Porosity,xe2x80x9d is a filing based upon U.S. Pat. No. 5,263,667, discussed further above, and claiming the priority thereof. The ""667 U.S. Patent is directed to a porous surface through which a fluid may be drawn for controlling the boundary layer; no movable surfaces are disclosed. The above noted discussion of the differences between the ""667 U.S. Patent and the present invention, is seen to apply to the disclosure of the ""093 European Patent Publication as well.
Finally, the inventors are aware of various papers published in the field which relate generally to the concept of the present invention. In addition to various other rotating cylinder leading and trailing edge developments, a paper by Modi et al. published in vol. 3, nos. 1-4 of Fluid Dynamics Research on Sep. 1, 1988 describes research in bound vortex boundary layer control by means of a rotating leading edge cylinder. Another paper by Modi et al. published in vol. 18, no. 11 of the Journal of Aircraft on Nov. 11, 1981 describes experiments conducted on a Canadair CL-84 using rotating cylinder wing and flap leading edges. No disclosure is made by Modi or others of whom the present inventors are aware in any technical papers, of the use of two independent movable surfaces disposed upon opposite surfaces of an airfoil or plane, nor of any porous surfaces for passing airflow therethrough, as provided by the present movable surface plane invention.
None of the above inventions and patents, either singly or in combination, is seen to describe the instant invention as claimed.
The present invention comprises a plane having movable opposite surfaces, as in a fixed or rotary airfoil for an aircraft, supporting or control surface for an airborne missile, fan blade or the like, control surface for a submersible or other maritime craft, etc. The present movable surface plane includes two separate, independent movable surfaces, with one extending over the majority of the upper or first surface of the airfoil or plane and the other extending across the majority of the opposite surface. Either of the upper or lower surfaces may cover part or all of the wing leading edge. The two movable surfaces are independent of one another, with each being movable in the same or opposite direction and/or at the same or a different velocity than the other. In addition, at least one of the movable surfaces is porous, with the passages therethrough communicating with fluid ducts or the like within the plane structure. The ducts provide either suction or pressure, respectively for drawing air or other fluid into or blowing air or, other fluid outwardly from the structure, as desired.
By moving the upper surface (or surface about which a lower pressure is desired) in the same direction as that of the slipstream or fluid flow about the plane, and the opposite surface in a direction opposite the fluid flow, the moving surfaces tend to accelerate the fluid flow over the surface moving with the flow, thereby further reducing the pressure upon that surface. The result is a force urging the plane toward the surface with the reduced pressure. The present movable surfaces are also operable on symmetrical surfaces with a zero angle of attack, due to the difference in velocity and thus pressure differential developed. However, they are advantageously applied to asymmetrical planes operating at some positive angle of attack, to provide even greater force than would be developed conventionally. Moving either of the upper or lower surfaces in the flow direction will lower drag by reducing shear stress.
The present disclosure also describes in general control and power means for operating the present movable surfaces, and various airfoil (or more generally, plane) configurations, such as tapered plan forms, swept configurations, etc., to which the present movable surfaces are adaptable. Power and control means for the suction or blowing of fluid through the porous surfaces, are also disclosed.
Accordingly, it is a principal object of the invention to provide an improved movable surface plane including movable surfaces disposed over the majority of a first and opposite second surface of the plane.
It is another object of the invention to provide an improved movable surface plane in which the movable surfaces may be actuated independently of one another to travel in the same or opposite directions and at the same or different velocities, as desired.
It is a further object of the invention to provide an improved movable surface plane adaptable for use with fixed and rotary wing aircraft (e.g., aerospace vehicles and helicopters), atmospheric missiles, submersible and other maritime vessels, stationary fans and windmills, and other fluid dynamic applications where differential pressure upon opposite sides of a lifting surface, control surface, or other surface is desired.
An additional object of the invention is to provide an improved movable surface plane including means for powering and actuating such surfaces.
Still another object of the invention is to provide an improved movable surface plane including means for controlling such surfaces for use as control devices for aircraft and marine craft.
Yet another object of the invention is to provide an improved movable surface plane including at least one porous surface and means for blowing or drawing a fluid through the porous surface for control of boundary layer flow over the surface.
It is an object of the invention to provide improved elements and arrangements thereof in an apparatus for the purposes described which is inexpensive, dependable and fully effective in accomplishing its intended purposes.
These and other objects of the present invention will become apparent upon review of the following specification and drawings.